IC13 UTI Flashcards
Define ASB
ASB (asymptomatic bacteriuria) - significant colony counts in urine but w/o urinary symptoms
Define UTI
significant colony counts in urine w urinary symptoms
In which patient populations should we screen for and treat ASB?
- pregnant women
increased chance of pyelonephritis, preterm labor, infant low birth weight if left untreated - undergoing invasive urologic procedure in which mucosal trauma/bleeding is expected
bacteria in urine may enter bloodstream, causing bacteremia & urosepsis
when treated, it is considered SAP
When do we screen for ASB in these 2 patient populations?
pregnant women: within 12-16 weeks of gestation
invasive urologic procedure: 2-3 days before procedure
How does UTI present in elderly patients?
- altered mental status (delirium, falls, confusion)
- urinary symptoms (eg. dysuria, frequency)
- signs of systemic infections
When do we treat UTI in elderly patients?
when they present with mental status changes + urinary symptoms OR signs of systemic infections
Describe the prevalence of UTIs across age groups
0-6 months: males > females
1-adult: females > males
elderly (>65): equal
Describe the possible routes of infection of bacteria that results in UTI
- ascending route
bacteria from colon/fecal matter colonise periurethral area/urethra –> ascend UP to bladder & kidney - descending route
bacteria from a distant primary infection site enters bloodstream and is transported to urinary tract, causing a UTI
What are the likely organisms involved in each route of infection?
ascending route: Enteric G(-) bacteria ie. Enterobacteriaceae, eg. E Coli, Klebsiella, Proteus
descending route: Staph aureus, MTb (bacteria unlikely to be found in GIT)
What are some host defence mechanisms in our body that prevents UTIs?
- bacteria stimulates micturition
- anti-adherence mechanisms
- antibacterial properties of urine & prostatic secretion
- presence of phagocytes
What are the risk factors for UTI?
- females > males
- sexual intercourse
- pregnancy
- use of diaphragms & spermicides
- previous UTI
- positive family history
- DM
- catheterization
- abnormalities in urinary tract (eg. prostatic hypertrophy, kidney stones)
- neurologic dysfunction eg. stroke, DM, spinal cord injuries
- anti-cholinergic drugs
How to prevent more UTIs (non-pharmacological strategies)
- hydrate adequately
- urinate frequently/go whenever you have the urge
- urinate right after sex
- good toilet hygiene (females - wipe from front to back)
- wear cotton underwear, loose-fitting clothes to keep the area dry; avoid tight fitting clothes
- avoid spermicides & diaphragms & unlubricated condoms
Classification of UTI
complicated vs uncomplicated
- complicated: a/w serious outcomes, treatment failure, disease relapse
eg. UTI in men, children, pregnant women
- uncomplicated: none of the above
typically pre-menopausal woman of child-bearing age with no history of abnormal urinary tract
What are the symptoms of lower UTI (cystitis)?
lower UTI (cystitis)
- dysuria (pain)
- hematuria (blood)
- urgency
- frequency
- nocturia
- suprapubic heaviness / pain
What are the symptoms of upper UTI (pyelonephritis)?
upper UTI (pyelonephritis)
- fever
- rigors
- headache
- N/V
- malaise
- flank pain
- renal punch positive
- abdominal pain
a/w systemic infection
What are the tests used to diagnose UTI?
urinalysis (UFEME)
urine dipstick
urine culture
lab values (WBC, RBC, CRP, procalcitonin, PMN)
What are the possible urine collection methods?
- midstream clean catch
- catheterization
- suprapubic bladder aspiration
What does the UFEME report measure?
- WBC
- RBC
- microorganisms
- WBC casts
- squamous epithelial cells
What do these indicators tell us?
- WBC
- > 10 WBCs/mm3 = pyuria (pus in urine) = presence of inflammation, though not necessarily due to infection
- no pyuria = very unlikely UTI - RBC
- > 5 RBC per high powered field (HPF) = hematuria
- frequently occurs in UTI but non-specific - microorganisms
- bacteria, yeast - WBC casts
- formed in renal tubules
- presence indicates upper UTI - squamous epithelial cells
- many = high levels of contamination = poor urine collection
What does the urine dipstick measure?
presence of
1. nitrites
- detects presence of G(-) bacteria
- requires at least 10^5 bacteria/mL
2. leukocyte esterases
- detects presence of leukocytes in urine
- correlates w significant pyuria (>10 WBCs/mm3)
When do we obtain urine cultures?
obtain pre-treatment cultures for complicated UTI (pregnancy, men, pyelonephritis, catheter-associated UTI) or recurrent relapse (relapse within 2 weeks)
When do we not obtain urine cultures?
do not obtain for uncomplicated UTI
What are the likely organisms involved in uncomplicated UTI?
- E Coli (80%)
- Staphylococcus saprophyticus
- Others (Proteus, Klebsiella, Enterococcus faecalis [PKE])
What are the likely organisms involved in complicated UTI?
- E Coli (50%)
- PKE
- Enterobacter
- Pseudomonas aeruginosa
What are the difference in the organisms involved in complicated and uncomplicated UTI?
TYPE of pathogens & STRAIN of pathogens (higher resistance in complicated/healthcare associated)
What are the UNlikely organisms involved UTI?
- Staph aureus: likely due to bacteremia (descending route)
- Yeast, Candida: likely contaminant; can consider other infection sites (can cause infection via descending route)
What is the thought process when trying to decide which abx to use for ASB/UTI?
- Do we need to treat this?
- ASB (except 2 special pop): NO
- Symptomatic: Yes - Likely organism
- Community acquired: E Coli, Staph saprophyticus
- Healthcare-associated: E Coli, PKE, Enterobacter, Pseudomonas - Type of UTI
- cystitis VS pyelonephritis
- complicated VS uncomplicated
- community acquired VS healthcare-associated
possible scenarios:
- cystitis in women
- community-acquired pyelonephritis in women
- community-acquired UTI in men
- healthcare-associated UTI
catheter-associated UTI
- UTI in pregnancy
Abx classes preferred for UTI in general according to SOA table
- beta lactams (penicillins, cephalosporins)
- fluoroquinolones
- co-trimoxazole
- others (nitrofurantoin, fosfomycin)
First line empiric treatment options for cystitis in women [uncomplicated]
Likely pathogen: E Coli
FIRST LINE
1. PO Co-trimoxazole 960mg BD x 3/7
2. PO Nitrofurantoin 50mg QDS x 5/7
3. PO Fosfomycin 3g single dose*
RESERVED FOR CYSTITIS DUE TO ESBL PRODUCING G(-)
[nitrofurantoin & fosfomycin for ucUTI ONLY]
Alternative empiric treatment options for cystitis in women [uncomplicated]
Likely pathogen: E Coli
ALTERNATIVES
1. PO Beta lactams x 5-7 days
- amoxicillin-clavulanate 625mg BD
- cephalexin 250-500mg QDS
- cefuroxime 250mg BD
2. PO Fluoroquinolones x 3/7
- cipro 250mg BD
- levo 250mg OD
*Avoid fluoroquinolones for ucUTI unless no other choice
(if can’t rmbr previous slide)
How to remember which abx to use for ucUTI in women:
Likely pathogen to target: E Coli
First line: Co-trimoxazole, nitrofurantoin, fosfomycin
Alternatives:
Referring to SOA table, the abx that targets E Coli are
* BETA LACTAMS
- Amox-clav
- Pip-tazo
- All cephalosporins
* Carbapenems
* Aminoglycosides
* Fluoroquinolones
Cystitis in women is simple, uncomplicated = use oral abx
Therefore, the only options left are
- Amox-clav
- Cephalexin
- Cefuroxime
- Fluoroquinolones
Pip-tazo is IV only, cefazolin + 3rd-5th gen cephalosporins are all IV, carbapenems & aminoglycosides reserved for ESBL
Technically fluoroquinolones can be used, BUT not preferred for uncomplicated UTI as risks > benefits
and now, the whole list of abx is magically generated via elimination :)
Empiric treatment options for cystitis in women [complicated]
same abx
longer duration of 7-14 days
fosfomycin dose for cUTI: PO 3g EOD x 3 doses
Empiric treatment options for community-acquired pyelonephritis in women: OUTPATIENT TREATMENT (ie. not very severe)
Likely pathogen: E Coli
OUTPATIENT TREATMENT (oral)
1. PO fluoroquinolones
- PO cipro 500mg BD x 7 days
- PO levo 750mg OD x 5 days
2. PO Co-trimoxazole 960mg BD x 10-14 days
3. PO Beta lactams x 10-14 days
- amoxicillin-clavulanate 625mg TDS
- cephalexin 500mg QDS (not preferred)
- cefuroxime 250-500mg BD
generally higher dose + longer duration compared to cystitis
Empiric treatment options for community-acquired pyelonephritis in women: INPATIENT TREATMENT (ie. severe)
Likely pathogen: E Coli
INPATIENT TREATMENT (IV)
considered for severely ill patients who require hospitalisation/unable to take oral drugs
- Amoxicillin-clavulanate 1.2g q8h
- Cefazolin 1g q8h
- Cipro 400mg BD
- IV/IM Gentamicin 5mg/kg
choose from 1, 2 or 3
add 4 if patient very severe = risk of ESBL strains
When and how do we step down IV abx for severe community-acquired pyelonephritis?
switch to oral abx (ie. non-severe options) when patient improves
- follow duration stated for oral abx
- eg. if switching to PO co-trimoxazole, which has a stated duration of 10-14 days, and patient has been on ACTIVE IV abx for 3 days, then administer co-trimoxazole for another 11 days
Empiric treatment options for community-acquired UTI in men
Likely pathogen: E Coli
concern for cystitis only: same treatment as complicated cystitis in women (co-trimoxazole, nitrofurantoin, fosfomycin for extended duration of 7-14 days)
concern for cystitis + ?prostatitis OR pyelonephritis:
1. PO co-trimoxazole 960mg BD
2. PO cipro 500mg BD
duration: 10-14 days
prostatitis confirmed: 6 weeks
why these 2 agents: concentrate well in all 3 organs (bladder, kidney, prostate) :O
co-trimoxazole:
What are the difference in doses + duration when used for
1. uncomplicated cystitis VS complicated cystitis
2. cystitis VS pyelonephritis
3. CA-UTI in men
dose is always the same at 960mg (2 tab) BD
1. uncomplicated - 3 days
complicated - 7-14 days
2. cystitis: 3 days / 7-14 days
pyelonephritis: 10-14 days
3. 10-14 days
Define nosocomial & healthcare-associated UTI
nosocomial: onset of UTI when hospitalised for >48h (2 days)
healthcare associated:
- hospitalised/underwent invasive urological procedures in the PAST 6 MONTHS
- indwelling urine catheter
- exposure to abx
What are the microbes of concern for nosocomial/healthcare-associated UTI?
- Pseudomonas aeruginosa
- Resistant bacteria (eg. ESBL E Coli, Klebsiella)
*MRSA is also a healthcare associated pathogen, but not of concern as not usually in urinary tract (unless from descending route of infection)
Empiric treatment options for healthcare-associated UTI for MORE sick patients
Likely pathogen: PA, ESBL
more sick = IV
1. IV Cefepime 2g q12h +/- IV Amikacin 15mg/kg/day
(if patient not doing well, add on aminoglycoside to cover potential ESBL strains)
(aminoglycoside may not be used in elderly due to concern of nephrotoxicity)
2. IV Carbapenem
- Imipenem 500mg q6h
- Meropenem 1g q8h
duration: 7-14 days
Empiric treatment options for healthcare-associated UTI for LESS sick patients
Likely pathogen: PA
less sick = oral
1. PO Fluoroquinolones
- Cipro 500mg BD
- Levo 750mg OD
(the only oral agent for PA)
duration: 7-14 days
What if a patient on PO abx for HA-UTI (ie. less severe) does not improve, or even worsens?
if worsens after 2 days/no improvement, switch to IV
Define catheter-associated UTI
- Signs & symptoms of UTI
- No other sources of infection
- at least 1 bacterial species in a single catheter urine specimen present in at least 10^3 cfu/mL
for patients that
- has been on catheter for 2 days
- within 2 days of removal of long term catheter
What are the symptoms of catheter-associated UTI?
- new-onset/worsening fever
- rigors
- altered mental status
- malaise
- lethargy
- no other identified cause (for the 5 above)
- flank pain
- costovertebral angle tenderness
- acute hematuria
- pelvic discomfort
Risk factors for catheter-associated UTI
- duration of catheterization
- colonisation of drainage bag, catheter, periurethral segment
- DM
- female
- impaired renal function
- poor quality of catheter care, incl insertion
What is the difference in the microbes identified from short term VS long term catheterization?
short term: UTI due to single microbe
long term: UTI due to multiple microbes (polymicrobial)
Scenario: Results of urine culture of patient with catheter showed presence of bacteria. What do you do?
asymptomatic –> NO NEED TO TREAT W ABX (similar to ASB)
1. remove catheter
2. if catheter is needed, replace
symptomatic –> TREAT
1. take urine +/- blood culture
2. start empiric abx
*if patient has low grade fever but is stable –> observe
Empiric treatment for moderate to severe symptomatic catheter-associated UTI
Likely pathogens: PA, ESBL
moderate to severe = IV
1. Carbapenems
- Imipenem 500mg q6h
- Meropenem 1g q8h
2. Cefepime 2g q12h +/- Amikacin 15mg/kg (1 dose or daily) (same as HA-UTI)
duration:
- 7 days (if fever goes down within 3 days)
- 10-14 days (if delayed response)
Empiric treatment for mild symptomatic catheter-associated UTI
Likely pathogen: PA, E Coli???
mild = oral
1. PO/IV levo 750mg OD x 5 days
2. PO Co-trimoxazole 960mg BD x 3 days
How to prevent catheter-associated UTI?
- avoid unnecessary catheter use
- use for minimal duration
- long term indwelling catheters should be changed before blockage occurs
- use of closed system
- ensure aseptic insertion technique
What is not recommended to prevent cather-associated UTI?
- topical antiseptic/antibiotic in urinary tract
- prophylactic abx
- chronic suppressive abx
What antibiotics should be avoided in pregnancy for UTI?
- fluoroquinolones
- co-trimoxazole
- nitrofurantoin at 38-42 wks
- aminoglycosides
What are the choice of abx & duration for UTI in pregnancy?
beta lactams
fosfomycin
What is the duration of treatment of UTI in pregnancy?
- ASB, cystitis: 4-7 days
- pyelonephritis: 14 days
What are some adjunctive therapy for symptoms experienced during UTI (pain, fever, vomiting)?
pain, fever - paracetamol, NSAIDs
vomiting - rehydration
pain - phenazopyridine 100-200mg TDS (topical analgesic effect) avoid in G6PD deficiency
How long will the abx take to show effect?
patient should feel better the next day (won’t completely be cured the next day, but should feel better)
